Abstract: Methods and systems are provided for improving the efficiency of canister purge completion. Based on engine operating conditions, a canister is purged to a compressor inlet or a throttle outlet. During purging conditions, as canister loads change, a purge flow through the canister is varied so that a fixed preselected portion of total engine fueling is delivered as fuel vapors.

Abstract: A purge valve and a fuel vapor management system for use with an engine emission control system are disclosed. The purge valve may include a first inlet for receiving a first flow of air from an air cleaner, a second inlet for receiving a second flow of purge vapors from an evaporative canister, and an outlet directing a controlled mixture of the first and second flows to an engine, upstream of an intake throttle. Relative amounts of the first flow and second flow may be selectively controlled by varying a position of the valve.

Abstract: Methods and systems are provided for conducting an engine off natural vacuum test in a vehicle in order to indicate the presence or absence of undesired evaporative emissions. In one example, a vehicle fuel system and evaporative emissions system are sealed from atmosphere, and responsive to a pressure increase below an expected threshold, the fuel system and evaporative emissions system are actively pressurized via circulating hot engine coolant to a heater core and blowing hot air through the vehicle cabin to the fuel system via a three way ventilation valve in the rear of the vehicle. In this way, false failures of EONV test procedures due to environmental factors and vehicle operator drive habits may be reduced, and unnecessary engine service may be avoided.

Abstract: Methods and systems are provided for improving the efficiency of canister purge completion. Based on engine operating conditions, a canister is purged to a compressor inlet or a throttle outlet. During purging conditions, as canister loads change, a purge flow through the canister is varied so that a fixed preselected portion of total engine fueling is delivered as fuel vapors.

Abstract: Methods and systems are provided for controlling the purging of a fuel vapor canister coupled to a vehicle fuel tank, configured for capturing and storing vapors emanating from the tank. In one example, two canister purge valves are coupled in series in a fuel vapor conduit between the fuel vapor canister and engine intake, one at the intake manifold and one at the fuel vapor canister, such that fine control over the introduction of fuel vapors into the engine is maintained via the purge valve at the intake manifold, while thorough purging of the fuel vapor canister may be regulated via the purge valve at the fuel vapor canister. In this way, fuel vapors in the fuel vapor canister may be effectively purged to intake, thus reducing the potential for undesired evaporative emissions.

Abstract: Methods and systems are provided for improving the efficiency of canister purge completion. Based on engine operating conditions, a canister is purged to a compressor inlet or a throttle outlet. During purging conditions, as canister loads change, a purge flow through the canister is varied so that a fixed preselected portion of total engine fueling is delivered as fuel vapors.

Abstract: Methods and systems are provided for controlling the purging of a fuel vapor canister coupled to a vehicle fuel tank, configured for capturing and storing vapors emanating from the tank. In one example, two canister purge valves are coupled in series in a fuel vapor conduit between the fuel vapor canister and engine intake, one at the intake manifold and one at the fuel vapor canister, such that fine control over the introduction of fuel vapors into the engine is maintained via the purge valve at the intake manifold, while thorough purging of the fuel vapor canister may be regulated via the purge valve at the fuel vapor canister. In this way, fuel vapors in the fuel vapor canister may be effectively purged to intake, thus reducing the potential for undesired evaporative emissions.

Abstract: Various methods and systems are provided for reducing pressure in a fuel tank of a fuel system of an engine. In one example, cooling fluid is routed from an air conditioner of a cooling system to a vapor cooler disposed in a vapor space of the fuel tank such that fuel vapor in the fuel tank may be condensed and routed to a fuel pump for delivery to the engine, thereby reducing a fuel tank pressure.

Abstract: Methods and systems are provided for conducting an engine off natural vacuum test in a vehicle in order to indicate the presence or absence of undesired evaporative emissions. In one example, a vehicle fuel system and evaporative emissions system are sealed from atmosphere, and responsive to a pressure increase below an expected threshold, the fuel system and evaporative emissions system are actively pressurized via circulating hot engine coolant to a heater core and blowing hot air through the vehicle cabin to the fuel system via a three way ventilation valve in the rear of the vehicle. In this way, false failures of EONV test procedures due to environmental factors and vehicle operator drive habits may be reduced, and unnecessary engine service may be avoided.

Abstract: A method, comprising: purging fuel vapors from a fuel vapor canister and/or a fuel vapor bleed element to an engine intake with air routed through a transmission bellhousing. In this way, purge air may be warmed by heat generated in the transmission bellhousing during engine operation, thereby increasing desorption efficiency and reducing bleed emissions. Further, purge air may be pressurized in the transmission bellhousing to allow purging operations irrespective of intake manifold vacuum.

Abstract: A method for operating a fuel system is disclosed. The method includes sequentially purging fuel vapors from each of a plurality of regions of a canister. Purging a region includes opening an air inlet valve associated with that region and maintaining air inlet valves associated with each other region closed to direct fuel vapors to at least one purge outlet.

Abstract: Methods and systems are provided for purging a multi-port canister into an engine intake. Air is circulated through the canister and a resulting purge air is directed to an intake passage upstream of a throttle in engine configured with a throttle body. An amount of fresh intake air received at the intake passage is corresponding decreased.

Abstract: A method, comprising: purging fuel vapors from a fuel vapor canister and/or a fuel vapor bleed element to an engine intake with air routed through a transmission bellhousing. In this way, purge air may be warmed by heat generated in the transmission bellhousing during engine operation, thereby increasing desorption efficiency and reducing bleed emissions. Further, purge air may be pressurized in the transmission bellhousing to allow purging operations irrespective of intake manifold vacuum.

Abstract: A vapor storage device is provided. The vapor storage device includes a diffuser plate positioned on an axis of an inlet port and comprising one or more openings extending through the plate from a leading edge to a trailing edge and a dome coupled to the inlet port of the device and the diffuser plate, where the dome includes side walls spaced away from the diffuser plate.

Abstract: Methods and systems are provided for improving the efficiency of canister purge completion. Based on engine operating conditions, a canister is purged to a compressor inlet or a throttle outlet. During purging conditions, as canister loads change, a purge flow through the canister is varied so that a fixed preselected portion of total engine fueling is delivered as fuel vapors.

Abstract: Methods and systems are provided for performing a vehicle-off fuel system leak test. A vehicle controller may be woken up after a vehicle has been in a key-off condition for a sufficient amount of time to monitor a fuel tank for pressure and temperature stabilization. If the pressure and temperature of the fuel tank is stable, a fuel pump may be operated to raise a fuel tank vapor pressure, and fuel system leaks are identified based on a rate of pressure decay from the fuel tank.

Abstract: A method for operating a fuel system is disclosed. The method includes sequentially purging fuel vapors from each of a plurality of regions of a canister. Purging a region includes opening an air inlet valve associated with that region and maintaining air inlet valves associated with each other region closed to direct fuel vapors to at least one purge outlet.

Abstract: A vapor storage device is provided. The vapor storage device includes a diffuser plate positioned on an axis of an inlet port and comprising one or more openings extending through the plate from a leading edge to a trailing edge and a dome coupled to the inlet port of the device and the diffuser plate, where the dome includes side walls spaced away from the diffuser plate.

Abstract: A method for operating a fuel system is disclosed. The method includes sequentially purging fuel vapors from each of a plurality of regions of a canister. Purging a region includes opening an air inlet valve associated with that region and maintaining air inlet valves associated with each other region closed to direct fuel vapors to at least one purge outlet.

Abstract: A method for operating an engine system is provided. The method includes maintaining an intake volume positioned upstream of a throttle and downstream of air cleaner within a selected operating pressure range through adjustment of a balance purge valve positioned upstream of the intake volume and a gas discharge source.